81223857237 has 32 divisors (see below), whose sum is σ = 112774348800. Its totient is φ = 51942764160.

The previous prime is 81223857229. The next prime is 81223857287. The reversal of 81223857237 is 73275832218.

It is not a de Polignac number, because 81223857237 - 2³ = 81223857229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81223857287) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16922764 + ... + 16927562.

It is an arithmetic number, because the mean of its divisors is an integer number (3524198400).

Almost surely, 2^81223857237 is an apocalyptic number.

It is an amenable number.

81223857237 is a deficient number, since it is larger than the sum of its proper divisors (31550491563).

81223857237 is a wasteful number, since it uses less digits than its factorization.

81223857237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6393.

The product of its digits is 1128960, while the sum is 48.

The spelling of 81223857237 in words is "eighty-one billion, two hundred twenty-three million, eight hundred fifty-seven thousand, two hundred thirty-seven".